Brake shoe



R. B. POGUE BRAKE SHOE March 31, 1936.

Filed May 16, 1934 Patented Mar. 31, 1936 UNITE STATES PAT BRAKE SHOEApplication May 16, 1934, Serial No. 725,893

7 Claims.

This invention relates to brake shoes which have a reenforce embedded inthe body at the back thereof.

Heretofore this reenforce has generally been a steel plate and the lugformed on the shoe to enable it to be attached to a brake head hasconsisted of a steel strap bent to form a keyway with its ends engagedbeneath the steel back. Projections from the shoe body have beenprovided to enclose the sides of the lug strap to protect and strengthenthe strap against deformation in handling and against cutting contactwith the brake head in service.

The plate back has been made as wide as possible for maximum strengthand a margin of about three-.eighths of an inch has been providedbetween each side edge of the plate back and the adjacent side of theshoe, which margin has been sufiicient to permit the body metal to makeanchoring engagement with the side edges of the plate back during thecasting operation but has not been suflicient to provide substantialanchorage for the projections at the sides of the attaching lug. Henceit has been the practice to recess or upset the side edges of the plateback to produce a satisfactory anchorage for the projections with thebody of the shoe, and this recessing or upsetting has necessarilyresulted in a corresponding reduction in the width and strength of theback. Sometimes the plate back has been cut out between the recessed orupset marginal edges to permit the body metal to form a projection inthe attaching lug, and such cutout further reduces the strength of theback.

One of the functions of the reenforcing back is to hold the parts of thebody together in case of fracture, which frequently occurs in service.The shoe is subjected to vibration in service and after the bodyfractures the effect of the vibration isconcentrated to a materialextent upon the back along the line of fracture. Since the body usuallyfractures at or close to the attaching lug the vibrations of the shoethereafter will be largely concentrated upon the back at probably itsweakest section where it is recessed or upset at its side margins andreduced in width and strength. The recessing or upsetting of themarginal edges of the back has been necessary to provide sufilcientanchorage for the lug projections with the body of the shoe but hasmaterially reduced the strength of the back where it is found inpractice that maximum strength should be provided.

The object of my invention is to avoid the practice of recessing orupsetting the plate back at the attaching lug and to provide a brakeshoe 7 with a plate back in which the marginal side edges of the backare continued without interruption or deformation beneath the attachinglug to preserve the strength of the back substantially 5 unimpaired atthe attaching lug.

And a further object of the invention is to provide a brake shoe with areenforce back imperforate at the bottom of the keyway of the attachinglug and having a projection of body metal 10 in the keyway and sideprojections connecting said keyway projection with the body of the shoe.

In the accompanying drawing illustrating a selected embodiment of theinvention Fig. 1 is a side view partly in section of a brake 1:; shoeembodying the invention.

Fig. 2 is a top plan view of the reenforce back showing the outline ofthe shoe in broken lines.

Figs. 3 and 4 are transverse sectional views on the lines 3-3 and G i,respectively, of Fig. 1.

Fig. 5 is a fragmentary view partly in section showing projections fromthe body metal in the keyway of the attaching lug.

Fig. 6 is a sectional view on the line 66 of Fig. 5.

Fig. 7 is a detail view of an end portion of a reenforce back showinganother form thereof.

Referring to the drawing, the body I of the shoe is generally made ofcast iron and sometimes it is provided with chill sections and sometimesit has inserts of different kinds embedded therein. The reenforcing back8 is made of a ductile metal plate which is embedded in the back of thebody. This plate has cut-outs 9 to receive the body metal for anchoringthe plate in the body. The center attaching lug comprises a lug strap I0bent to form a keyway with its end portions ll pro-- jected throughparallel longitudinal slots I2 in the back and bent inwardly against theunderside of the back.

The marginal side edges E3 of the back are depressed providing a crownedcentral portion l4 therebetween. The crowned portion It lies in asurface above the surface of the depressed marginal edges of the backand is generally flush with the back of the body. These marginal side.edges of the back are not recessed or upset at the attaching lug butare continuous at the attaching lug and throughout at least the-centralportion of the shoe and preferably throughout the length of the back.Nor is the back out out at the bottom of the keyway but it is leftimperforate and the slots l2 extend lengthwise of the back and are ofjust suflicient width to receive the side portions of the lug strap.Therefore the width of the reenforcing back is maintained at andadjacent the attaching lug and the strength of the back is not reducedby recessing or upsetting the marginal edges of the back at theattaching lug.

Projections l5 of body metal are formed as usual at the sides of theattaching lug but these projections are enlarged at l6 by increasingtheir width so that they will extend beyond the planes of the sides ofthe body (Fig. 4) This enlargement in width of the projections providesample anchorage of the projections with the body metal and avoids thenecessity for recessing or upsetting the marginal side edges of the backat the attaching lug for this purpose. Therefore the width of thereenforce back may be maintained at the attaching lug without recessingor upsetting the marginal edges thereof and without reducing thestrength of the back at the attaching lug where it is most needed forresisting the strains of vibrations in service after the body of theshoe fractures.

The projections may extend lengthwise of the shoe and beyond the edgesof the lug strap, as

shown in Figs. 2 and 5, and this permits body metal to flow aroundthe-edges of the lug strap and form a projection IT at the bottom of thekeyway in the attaching lug, Figs. 5 and 6, if desired.

I prefer that the depressed marginal side edges of the reenforce back becontinued to the ends thereof as shown in Fig. 2 but for some purposesit may be desirable to provide the back with fiat ends l8 as shown inFig. '7.

My invention avoids the practice of reducing the strength of thereenforce back by recessing or upsetting the marginal side edges thereofat the attaching lug and preserves the width and strength of the back atthe attaching lug. The slots l2 extend lengthwise of the back and do notmaterially reduce the transverse strength of the back. This result ismade possible by increasing the width of the projections of body metalat the sides of the attaching lug whereby ample anchorage of .theprojections with the body of the shoe is provided to prevent theprojections from being broken off in the handling or service of theshoes. The projections I! in the keyway also add to the strength of theprojections l6 at the sides of the attaching lug and increase theanchorage of the projections to the body of the shoe.

I do not intend to restrict the invention to the simple form of freightcar shoe which has been selected for the purpose of illustrating anddescribing it; I appreciate the fact that the invention may be embodiedin a variety of ways in different kinds of shoes; and I reserve theright to make all such changes and embodiments of and a center attachinglug, said plate having its marginal side edges depressed at theattaching lug and wholly enclosed within the body of the shoe.

2. A brake shoe having a body, a reenforce plate anchored to the body atthe back thereof, and a center attaching lug, said plate having itsmarginal side edges depressed between the end portions of the shoe andat the attaching lug and wholly enclosed within the body of the shoe.

3. A brake shoe having a body, a reenforce plate anchored to the body atthe back thereof, and a center attaching lug, said plate having itsmarginal side edges depressed and wholly enclosed within the body of theshoe at the attaching lug andthroughout the length of the back.

4. A brake shoe having a body, a reenforce plate anchored to the body atthe back thereof, and a; center attaching lug, said plate having itscentral portion in one surface and its marginal side edges depressed inanother surface and extending outwardly from the central portion at theattaching lug and wholly enclosed within the body of the shoe.

5. A brake shoe having a body, a reenforce plate of less width thanthe-body and anchored to the body at the back thereof, and a centerattachinglug, the marginal side edges of the plate beingdepressed belowthe central-portion at the attaching lug and wholly enclosed within thebody'of the shoe.

6. A brake shoe having a body, and a reenforce plate of less width thanthe body and anchored to the body at the back thereof, said plate havingits marginal side edges projecting outwardly from the intermediateportion ofthe plate and depressed below said intermediate portion andembedded in the body of the shoe throughout at least the central portionof the back.

body of theshoe to solidly embed the depressed marginal side edges ofthe back opposite the lug strap and form ample anchorage of theprojections with the body.

ROBERT B. POGUE.

